1. Field of the Invention
This invention relates to a wiper apparatus for wiping the windshield of a vehicle.
2. Description of the Prior Art
A known example of a conventional wiper apparatus of this type is disclosed in the specification of Japanese Patent Application Laid-Open (KOKAI) No. 63-82860. This conventional wiper apparatus includes a rotatably supported main shaft to which a wiper arm is secured, a lever secured to the main shaft, and a drive mechanism connected to the lever via a rod. The rod is pushed and pulled by operation of the drive mechanism, and the main shaft is rotated via the lever by the pushing and pulling of the rod. As a result, the wiper arm is swept back and forth between upper and lower reversal points to wipe off a windshield.
Ordinarily, the upper reversal point of the wiper arm is set just short of the pillar of the vehicle in order to assure good visibility. With a wiper apparatus of this type, however, considerable wind force acts upon the wiper arm when the apparatus is used at, say, a high vehicle traveling velocity. As a consequence, the wiper arm may overshoot the normal upper reversal point owing to the force of the wind and reverse at a position beyond this point. This can cause the wiper blade to strike the vehicle pillar and sustain damage as a result. There is also the danger that the wiper arm may swing beyond the pillar and operate abnormally.